# Solar Sphere vs Astro PM

The clearest difference is update cadence: Astro PM at fortnightly against Solar Sphere's every 9 months. Solar Sphere's advantage is device support (4 vs 2) and iOS requirement (9.0 vs 15.0). On price, ads and in-app purchases there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

Solar Sphere ships an update every 9 months, Astro PM fortnightly. The most recent releases landed on October 17, 2026 and October 18, 2026 respectively.

## The numbers

| Metric | Solar Sphere | Astro PM |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.1 (7 ratings)](https://appshunter.io/ios/app/solar-sphere/id990396823/reviews)** | — |
| Number of ratings | **7** | — |
| Positive reviews | 44.4% of reviews | — |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 9 months | **Fortnightly** |
| Monetization | Free | — |
| Size | 3 MB | 49 MB |
| Requires iOS | **9.0** | 15.0 |
| Devices | **iPhone, iPad, iPod, Apple Watch** | iPhone, iPod |
| Age rating | 17+ | 4+ |
| Developer | [Pulsely Consulting](https://appshunter.io/developer/475349326) | [Josh Jones](https://appshunter.io/developer/6804066612) |

## What reviewers say

### Solar Sphere

[App page](https://appshunter.io/ios/app/solar-sphere/id990396823)

Monitor real-time solar activity with Kp-index data and high-resolution solar images. Understand geomagnetic disturbances and their impact on Earth's magnetic field. Ideal for drone pilots needing to check conditions before flying.

**Highlights:** Real-time Kp-index monitoring, High-resolution solar images, Kp-index explanation, Geomagnetic storm indication, Drone flying safety guidance

**Features:** macOS Compatibility, Apple Watch app, Vision Pro support

**In-app purchases:** none


### Astro PM

[App page](https://appshunter.io/ios/app/astro-pm/id6804066610)

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


## Frequently asked questions

### Is Solar Sphere free?

Solar Sphere is free to download, with no in-app purchases.

### Is Astro PM free?

Astro PM is free to download, with no in-app purchases.

### Do Solar Sphere or Astro PM have ads?

Neither Solar Sphere nor Astro PM shows ads.

### Which is updated more often, Solar Sphere or Astro PM?

Solar Sphere ships an update every 9 months, and Astro PM fortnightly. Most recently, Solar Sphere was updated on October 17, 2026 and Astro PM on October 18, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*